Display device, image processing device and image processing method, and computer program

ABSTRACT

There is provided a display device including a display unit that displays an image thereon, an eyepiece optical unit that projects a display image of the display unit on the eyes of a user, a correction information retaining unit that retains correction information created in advance according to a state of the user, and a distortion correction unit that corrects distortion of the display image based on correction information according to a current state of the user.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a national phase entry under 35 U.S.C. §371of International Application No. PCT/JP2012/083736 filed Dec. 26, 2012,published on Sep. 26, 2013 as WO 2013/140697 A1, which claims priorityfrom Japanese Patent Application No. JP 2012-064899 filed in theJapanese Patent Office on Mar. 22, 2012.

TECHNICAL FIELD

The technology disclosed in the present specification relates to adisplay device, for example, a head-mount display in which displaypanels and lenses are combined, an image processing device and an imageprocessing method, and a computer program, and particularly to a displaydevice, an image processing device and an image processing method, and acomputer program which correct distortion of images caused by a state ofa user or differences between individual users.

BACKGROUND ART

A display device which is worn on a head for viewing images, in otherwords, a head-mount display (HMD), has been widely known. Such ahead-mount display is configured to have optical units each for the leftand right eyes, and to be able to control the senses of viewing andhearing by also using a headphone. If such a device is configured tocompletely block the outside world when mounted on a head, a feeling ofvirtual reality during viewing increases. In addition, as a head-mountdisplay can also project different images to the right and left eyes, 3Dimages can be presented when images having parallax are displayed forthe right and left eyes.

For a display unit of a head-mount display for the right and left eyes,high-definition display panels which include, for example, liquidcrystal or organic EL (Electro-Luminescence) elements, or the like canbe used. In addition, if a wide angle of view is set by enlarging andprojecting image display elements with an eyepiece optical system, andmulti-channels are realized using a headphone, a rich feeling ofpresence in a movie theater for viewing and listening can be reproduced.

Since there are differences among individual users in heights andintervals of eyes and a head-mount display has independent eyepieceoptical systems for the right and left sides, it is necessary to matchthe positions of the eyepiece optical systems with those of the eyes ofa user wearing the device. Since large screens are projected in front ofthe eyes, when reproduced video images of a Blu-ray disc, or the likeare watched for a long period of time, it is preferable to preciselymatch the position of the images projected from a head-mount displaywith the eye interval to keep the eyes healthy.

For example, a head-mount display which has an eye interval adjustingmechanism using a rack-and-pinion method in response to differencesbetween individual users has been proposed (for example, refer to PatentLiterature 1). In addition, a head-mount display which has a rotaryshaft between a left-eye display unit and a right-eye display unit isprovided with a rotary member that is connected to each of the displayunits via arms, and includes an eye interval adjusting mechanism thatadjusts the distance between the left-eye display unit and the right-eyedisplay unit so as to be symmetric on the right and left sides byrotating the rotary member has been proposed (for example, refer toPatent Literature 2).

In addition, the specification of Japanese Patent Application No.2010-287835 (Patent Literature 3), which has already been transferred tothe present applicant, proposes a head-mount display which can preciselyadjust an eye interval with a direct operation of an eye intervaladjusting mechanism by a user wearing the device. Since this head-mountdisplay displays a signal pattern for eye interval adjustment while theeye interval is adjusted, the user can more precisely adjust the eyeinterval by operating the eye interval adjusting mechanism by himself orherself while observing the signal pattern.

When the lens centers of eyepiece optical systems do not match thecenter positions of the eyes, the mismatch causes a part or all of adisplayed image to appear distorted, or each of R, G, and B to appearshifted in a part or all of a screen due to magnification chromaticaberrations of lenses.

However, even when an eye interval adjusting mechanism is provided, itis difficult to precisely match the lens centers of the eyepiece opticalsystems and the center positions of the eyes. In addition, when it isnot possible in the eye interval adjusting mechanism to adjust thepositions with no stages, but only to fix the positions in stages, thereare users for whom the eye interval is not able to be adjusted at all.

The problem of adjusting an eye interval as described above can besolved by using a lens which causes little distortion and magnificationchromatic aberrations even if the lens centers do not match the centerpositions of the eyes. However, such a lens incurs a high manufacturingcost. In addition, since the weight of the lens becomes heavy, a feelingof wearing the head-mount display becomes worse.

Alternatively, such a problem of adjusting an eye interval can be solvedby employing an eye interval adjusting mechanism which can adjustpositions with no stages, but the employment causes the mechanism to becomplicated, resulting in an increase in the device cost.

CITATION LIST Patent Literature

Patent Literature 1: JP H6-276459A

Patent Literature 2: Japanese Patent No. 4609256

Patent Literature 3: JP 2012-138654A

SUMMARY OF INVENTION Technical Problem

It is desirable to provide an excellent display device, an imageprocessing device and an image processing method, and a computer programwhich can appropriately correct distortion of images caused by a stateof a user or differences between individual users.

It is further desirable to provide an excellent display device, imageprocessing device and image processing method, and computer programwhich can appropriately correct distortion of images which is caused bymismatch of the centers of lenses projecting displayed images and thecenter positions of the eyes of a user observing the projected imageswhen the images are displayed using a combination of display panels andthe lenses.

Solution to Problem

The present technology is provided to solve the above-mentioned issues.According to the technology described in claim 1 of the presentapplication, there is provided a display device including a display unitthat displays an image thereon, an eyepiece optical unit that projects adisplay image of the display unit on the eyes of a user, a correctioninformation retaining unit that retains correction information createdin advance according to a state of the user, and a distortion correctionunit that corrects distortion of the display image based on correctioninformation according to a current state of the user.

According to the technology described in claim 2 of the presentapplication, the correction information retaining unit described inclaim 1 may retain, as the correction information, a correction vectorfor correcting distortion of the display image caused by an amount ofshift between the lens center of the eyepiece optical unit and thecenter positions of the eyes of a user. The distortion correction unitmay correct the display image based on the correction vector accordingto the amount of shift between the lens center of the eyepiece opticalunit and the center positions of the eyes of the user.

According to the technology described in claim 3 of the presentapplication, the display device described in claim 1 may further includean eye interval adjusting mechanism that adjusts a position of thedisplay unit with respect to the eye interval of a user in stages. Thecorrection information retaining unit may retain, as the correctioninformation, a correction vector for correcting distortion of thedisplay image caused by an amount of shift of an interpolation positionthat is obtained by interpolating the interval of the stepwiseadjustment position by the eye interval adjusting mechanism. Thedistortion correction unit may correct the display image based on acorrection vector according to an amount of shift of the interpolationposition remaining after the eye interval adjusting mechanism performsthe adjustment.

According to the technology described in claim 4 of the presentapplication, the correction information retaining unit described inclaim 1 may retain, as the correction information, a correction vectorfor correcting distortion of the display image caused by an aberrationunique to glasses. The distortion correction unit may correct thedisplay image based on a correction vector corresponding to the glassesthat a user wears.

According to the technology described in claim 5 of the presentapplication, the correction information retaining unit described inclaim 1 may retain, as the correction information, a correction vectorfor correcting distortion of the display image caused by the differencebetween an appropriate distance in terms of lens design for the distancedirection between a lens of the eyepiece optical unit and the eyes of auser and the distance of the individual user. The distortion correctionunit may correct the display image based on the correction vector.

Further, according to the invention described in claim 6 of the presentapplication, there is provided an image processing device including acorrection information retaining unit that retains correctioninformation created in advance according to a state of a user, and adistortion correction unit that corrects distortion of a display imagebased on correction information according to a current state of theuser.

Further, according to the invention described in claim 7 of the presentapplication, there is provided an image processing method includingretaining correction information that is created in advance according toa state of a user, and correcting distortion of a display image based oncorrection information according to a current state of the user.

Further, according to the invention described in claim 8 of the presentapplication, there is provided a computer program that is described in acomputer-readable form so as to cause a computer to function as acorrection information retaining unit that retains correctioninformation created in advance according to a state of a user, and adistortion correction unit that corrects distortion of a display imagebased on correction information according to a current state of theuser.

The computer program according to claim 8 of the present application isdefined as a computer program described in a computer-readable form soas to realize a predetermined process on a computer. In other words, byinstalling the computer program according to claim 8 of the presentapplication in a computer, a cooperative action is exhibited on thecomputer, and thereby the same advantageous effect as that of the imageprocessing device according to claim 5 of the present application can beobtained.

Advantageous Effects of Invention

According to the technology disclosed in the present specification, anexcellent display device, image processing device and image processingmethod, and a computer program which can appropriately correctdistortion of an image caused by differences between individual users orstates of the users when the image is displayed using a combination ofdisplay panels and lenses can be provided.

In addition, according to the technology disclosed in the presentspecification, an excellent display device, image processing device andimage processing method, and a computer program which can appropriatelycorrect distortion of an image caused by mismatch of the centers oflenses projecting a display image and the center positions of the eyesof a user who observes the projected image when the image is displayedusing a combination of display panels and lenses can be provided.

According to the technology disclosed in the present specification, adistortion correction vector according to an amount of shift between thelens center of the eyepiece optical system and the center position of aneye can be created in advance, and an image can be corrected using acorrection vector according to an amount of actual shift when a userwears the display device.

According to the technology disclosed in the present specification, byallowing a certain degree of distortion and a magnification chromaticaberration occurring in an observed image and supplementing the allowedportion with image correction, a manufacturing cost of a lens can belowered, or the weight of a lens can be reduced.

In addition, according to the technology disclosed in the presentspecification, by supplementing fine adjustment of an eye interval withimage correction, a configuration of the eye interval adjustingmechanism can be simplified, and a cost can be reduced.

In addition, according to the technology disclosed in the presentspecification, with regard to the distance direction between a lens ofthe eyepiece optical unit and the eyes of a user, an aberration causedby a difference between an appropriate distance in terms of lens designand the distance of an individual user that varies depending on userscan be compensated through image correction.

The technology disclosed in the present specification can respond tovarious aberrations caused by a state of a user or differences betweenindividual users by changing the correction vectors. For example, when aperson who wears glasses uses a head-mount display, there are cases inwhich the user sees an aberration unique to the glasses and thus failsto observe a correct image. In such a case, by measuring the aberrationof the glasses in advance and superimposing the aberration on thedistortion correction vector, a correct image obtained by correcting theaberration can be presented even when wearing the glasses.

Other objects, features, and advantages of the present invention will befurther apparent with detailed description based on later-mentionedembodiments of the present invention and attached drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an illustration schematically showing a configuration of animage display system including a head-mount display.

FIG. 2 is an illustration showing a state in which a top side of themain body of a head-mount unit 10 equipped with an eye intervaladjusting mechanism is overlooked.

FIG. 3 is an illustration exemplifying an image observed when the lenscenter of an eyepiece optical system matches the center position of aneye.

FIG. 4 is an illustration exemplifying an image observed when the lenscenter of the eyepiece optical system does not match the center positionof the eye.

FIG. 5A is an illustration showing a displayed image after an inputimage is corrected based on a correction vector when the lens center ofthe eyepiece optical system does not match the center position of theeye.

FIG. 5B is an illustration showing an image obtained by observing thedisplayed image after the correction shown in FIG. 5A through the lens.

FIG. 6 is an illustration schematically showing a configuration of aprocessing system for a video signal in a head-mount display.

FIG. 7 is an illustration for describing a structure of eye intervaladjustment performed by an eye interval adjusting mechanism.

FIG. 8 is an illustration for describing a structure of interpolating agap between eye interval adjustment positions performed by the eyeinterval adjusting mechanism.

FIG. 9 is an illustration showing a corrected image when the lens centerof an eyepiece optical system 604 matches the center position of an eye.

FIG. 10 is an illustration showing a corrected image when the centerposition of an eye is shifted to the left side of the lens center of theeyepiece optical system 604 by 4 mm.

FIG. 11A is an illustration for describing a procedure of performinginterpolation of the eye interval adjusting mechanism.

FIG. 11B is an illustration for describing another procedure ofperforming interpolation of the eye interval adjusting mechanism.

FIG. 11C is an illustration for describing still another procedure ofperforming interpolation of the eye interval adjusting mechanism.

DESCRIPTION OF EMBODIMENT

Hereinafter, a preferred embodiment of the present invention will bedescribed in detail with reference to the appended drawings. Note that,in this specification and the drawings, elements that have substantiallythe same function and structure are denoted with the same referencesigns, and repeated explanation is omitted.

FIG. 1 schematically shows a configuration of an image display systemincluding a head-mount display. The system shown in the drawing isconstituted by a Blu-ray disc reproduction device 20 that serves as asource of viewing content, a front-end box 40 that processes AV signalsoutput from the Blu-ray disc reproduction device 20, a head-mountingtype display device (head-mount unit) 10 that is an output destinationof reproduced content of the Blu-ray disc reproduction device 20, and ahigh-vision display (for example, an HDMI-compatible television) 30 thatis another output destination of the Blu-ray disc reproduction device20. One head-mount display is configured by the head-mount unit 10 andthe front-end box 40.

The front-end box 40 corresponds to an HDMI repeater that, for example,processes AV signals output from the Blu-ray disc reproduction device 20and outputs the signals to an HDMI port when an HDMI input of the AVsignals is received. In addition, the front-end box 40 is a 2-outputswitcher that switches the output destination of the Blu-ray discreproduction device 20 to any one of the head-mount unit 10 or thehigh-vision display 30. The front-end box 40 has two outputs in theexample of the drawing, but may have three or more outputs. However, thefront-end box 40 has an exclusive output destination of AV signals, andputs priority on output to the head-mount unit 10.

Note that HDMI (High-Definition Multimedia Interface) is an interfacestandard for digital home appliances mainly for transmitting sounds andvideos based on DVI (Digital Visual Interface) using TMDS (TransitionMinimized Differential Signaling) in a physical layer. The presentsystem is based on, for example, an HDMI 1.4 specification.

The Blu-ray disc reproduction device 20 and the front-end box 40, andthe front-end box 40 and the high-vision display 30 are respectivelyconnected to each other with HDMI cables. The front-end box 40 and thehead-mount unit 10 can also be configured to be connected with an HDMIcable, but AV signals may be serially transmitted therebetween using acable of other specifications. However, AV signals and power may be setto be supplied to one cable connecting the front-end box 40 and thehead-mount unit 10, and the head-mount unit 10 can obtain drive powervia the cable.

The head-mount unit 10 has independent display units for the left eyeand the right eye. Each of the display units uses a display panelincluding, for example, organic EL elements. In addition, each of theleft and right display units is equipped with a high-definition eyepieceoptical system which causes low distortion and has a wide viewing angle.If a wide angle of view is set by enlarging and projecting image displayelements with the eyepiece optical system, and multi-channels arerealized using a headphone, a rich feeling of presence in a movietheater for viewing and listening can be reproduced.

Since there are differences between individual users in heights andintervals of eyes, and the head-mount unit 10 has the independentoptical systems for the right and left sides, it is necessary to matchpositions of the optical systems with those of the eyes of a userwearing the unit. For this reason, in the present embodiment, the mainbody part of the head-mount unit 10 is equipped with an eye intervaladjusting mechanism which adjusts eye intervals between the right-eyedisplay unit and the left-eye display unit. To speak in terms of therelationship between the right and left eyes and the display units, theeye interval adjusting mechanism adjusts the positions of the displayunits for the eye interval of a user. FIG. 2 shows a state in which atop side of the main body part of the head-mount unit 10 equipped withthe eye interval adjusting mechanism is overlooked.

A component of a mechanism may be used for mounting the eye intervaladjusting mechanism. However, a mechanism that is used for binocularsand microscopes for adjusting eye intervals with one eye intervaladjustment axis arranged between right and left barrels is notpreferable due to the fact that the height from a nose pad part (inother words, the position of the user's nose) to the display unitschanges according to the rotation of the eye interval adjustment axis.On the other hand, the configuration of the eye interval adjustmentmechanism using, for example, the rack-and-pinion method is favorablesince the height from the nose pad part to the display units can beconstantly maintained during adjustment of eye intervals. However, thegist of the technology disclosed in the present specification is notlimited only to the rack-and-pinion method, and an eye intervaladjusting mechanism using another method is possible as long as there isno inconvenience in changing the height of the display units when an eyeinterval is adjusted.

Here, in a display device such as a head-mount display in which displaypanels and lenses are combined, there is a problem of distortionoccurring when a display image is observed through lenses due to lensdistortion and a magnification chromatic aberration. In the field of thecorresponding technology, a method of correcting distortion throughsignal processing is known. In other words, by imparting distortion to adisplay image in the opposite direction of a distortion characteristicof an eyepiece optical system, a normal image that does not includedistortion can be observed when viewed through the eyepiece opticalsystem. Distortion in the opposite direction imparted to each pixel ofan input image is hereinafter called a “correction vector.” A correctionvector has a pixel position on an input image as a beginning point andhas a pixel position corresponding to the beginning point on a displayimage as an end point.

In addition, when the lens centers of eyepiece optical systems do notmatch the center positions of the eyes, the mismatch causes a part orall of a display image to appear distorted, or each of R, G, and B toappear shifted in a part or all of a screen due to a magnificationchromatic aberration of lenses.

FIG. 3 exemplifies an image observed when the lens center of an eyepieceoptical system matches the center position of an eye. Conversely, FIG. 4exemplifies an image observed when the lens center of the eyepieceoptical system does not match the center position of the eye. In theformer example, a white-lined lattice image displayed on a display panelis correctly observed through a lens. However, in the latter example,the center position of the eye is shifted from the lens center to theleft side, a magnification chromatic aberration occurs on the right edgeof a screen, and from a green signal, red is shifted on the right side,and conversely, blue is shifted to the left side.

Sometimes it is difficult for a user to precisely match the lens centersof eyepiece optical systems with the center positions of the eyes. Inaddition, when an eye interval adjusting mechanism is not able to adjusta position with no stages, but only to fix a position in stages, someusers may not be able to precisely adjust an eye interval at all. An eyeinterval adjusting mechanism that can adjust a position with no stageshas a complicated structure, which results in an increasing device cost.When lenses that do not cause distortion or magnification chromaticaberrations are used, although the centers of the lenses may be allowednot to match the center positions of the eyes, the device costincreases, and a feeling of wearing the device deteriorates due to aweight increase of the lenses.

Thus, in the present embodiment, a distortion correction vectoraccording to an amount of shift between the lens centers of the eyepieceoptical systems and the center positions of the eyes is set to becreated in advance. Then, by correcting an input image using thecorrection vector according to the amount of shift between the lenscenters of the eyepiece optical systems and the center positions of theeyes when a user wears the head-mount unit 10, an image that does nothave distortion or color shifts is presented.

FIG. 5A shows a display image after an input image is corrected based ona correction vector when the lens center of the eyepiece optical systemdoes not match the center position of the eye. In addition, FIG. 5Bshows an image obtained by observing the displayed image through thelens. As described with reference to FIG. 4, due to the mismatch of thelens center and the center position of the eye, a magnificationchromatic aberration in which red is shifted to the right side, and blueis shifted to the left side from a green signal occurs, and thus, thecorrection vector causes red to be shifted to the left side and blue tobe conversely shifted to the right side from the green signal as shownin FIG. 5A. Then, when the corrected image is observed through the lens,a correct white-lined lattice can be seen as shown in FIG. 5B.

FIG. 6 schematically shows a configuration of a processing system for avideo signal in a head-mount display. Even though the drawingillustrates the system only for one side of the left eye or the righteye, configurations for the eyes are the same.

A display unit 603 has a high-definition display panel including, forexample, liquid crystal, organic EL (Electro-Luminescence) elements, orthe like. In addition, an eyepiece optical system 604 enlarges andprojects display videos of the display unit 603. A lens constituting theeyepiece optical system 604 is designed based on, for example, a resultof optical simulation.

A video reduction unit 601 processes input video signals to be reducedso that the signals are appropriate for the size of a display panel. Adistortion correction unit 602 corrects input images from the videoreduction unit 601 based on a correction vector according to mismatch ofthe lens center of the eyepiece optical system 604 with the centerposition of an eye.

A correction vector retaining unit 605 stores correction vectors createdin advance. The correction vector retaining unit 605 stores one or morecorrection vectors created in advance such as a correction vector forcorrecting lens distortion or a magnification chromatic aberration ofthe eyepiece optical system 604, and a correction vector for correctinga magnification chromatic aberration based on the mismatch of the lenscenter of the eyepiece optical system 604 with the center position ofthe eye. The distortion correction unit 602 can also correct an inputimage by superimposing two or more correction vectors stored in thecorrection vector retaining unit 605 if necessary.

FIG. 7 illustrates a structure of eye interval adjustment performed byan eye interval adjusting mechanism. The eye interval adjustingmechanism is set to be able to adjust a position in stages with apredetermined interval G1 as a unit of scale in the range of ±2 from theinitial position 0. In the example of the drawing, at the positions ofthe scale +1, the lens centers match the center positions of the eyes.

However, when the eye interval adjusting mechanism is not able to adjustpositions with no stages, the lens centers do not necessarily match thecenter positions of the eyes at any positions of scales. In the exampleshown in FIG. 8, by adjusting the positions of +1 within the scale G1,the lens centers are brought nearest to the center positions of theeyes, but do not completely match them. In other words, even when an eyeinterval is adjusted using the eye interval adjusting mechanism, thereis a possibility of a shift less than a gap of stepwise adjustmentpositions remaining. If such mismatch is neglected, a magnificationchromatic aberration occurs in an observed image as shown in FIG. 4.

Thus, correction vectors for correcting magnification chromaticaberration caused by mismatch of an interval G2 that is smaller than theunit of a scale G1 (G2<G1) of position adjustment by the eye intervaladjusting mechanism are generated in advance and stored in thecorrection vector retaining unit 605. After the eye interval is adjustedusing the eye interval adjustment mechanism as much as possible and thedistortion correction unit 602 corrects an image according to thecorrection vectors, distortion can be corrected so that the minimuminterval G1 of position adjustment performed by the eye intervaladjusting mechanism is interpolated.

In the example shown in FIG. 8, correction vectors in interpolationpositions of ±1 in the unit of the interval G2 are prepared in advancefor each of the scales of position adjustment. Then, the lens centersare brought nearest to the center positions of the eyes when the eyeinterval adjusting mechanism adjusts the lens centers to be in theposition of the scale +1, however, when the mechanism is shifted fromthe scale G2 of the interpolation position by −1, the correction vectorfor “−1” is applied to perform fine adjustment in the interval G2, andthereby magnification chromatic aberration can be suppressed.

FIG. 9 shows a corrected image when the lens center of the eyepieceoptical system 604 matches the center position of an eye (in thedrawing, narrow dotted lines correspond to red, wide dotted linescorrespond to blue, and dashed lines correspond to green). Meanwhile, anoriginal image before correction is set to be the white-lined latticeimage. Since distortion and magnification chromatic aberration arecorrected separately for each of R, G, and B, the positions of R, G andB are slightly shifted in a corrected image. In addition, since theamount of distortion increases toward the periphery of the image, theamount of shift of each color component increases. As the image isviewed through the eyepiece optical system 604, a correct white-linedlattice image can be seen.

In addition, FIG. 10 shows a corrected image when the center position ofan eye is shifted to the left side of the lens center of the eyepieceoptical system 604 by 4 mm (in the drawing, narrow dotted linescorrespond to red, wide dotted lines correspond to blue, and dashedlines correspond to green). Meanwhile, an original image beforecorrection is set to be the white-lined lattice image. In this case, inaddition to correction of distortion and magnification chromaticaberration performed separately for each of R, G, and B, a shift of thecenter position of the eye is corrected. A corrected image in which thepositions of R, G, and B are slightly shifted is obtained, but thepositions of R, G, and B on the right edge of the corrected image areshifted, and thus the corrected image becomes different from the imagebefore the correction. In the example shown in the drawing, since theshifts of red and blue from green are made in a decreasing direction,the amounts of shifts of R, G and B on the right edge of the correctedimage are smaller than the example shown in FIG. 9.

An example of the procedure for performing the interpolation of the eyeinterval adjusting mechanism will be described with reference to FIGS.11A to 11C. In a state in which white-lined lattice images are displayedon right and left display panels, for example, a user performsmechanical eye interval adjustment in the minimum interval G1 using theeye interval adjusting mechanism, and selects positions of the lenscenters nearest to the centers of the eyes. Next, images obtained bycorrecting the white-lined lattice images using correction vectors ofeach of the positions −1, 0, and +1 in the scale G2 for interpolatingthe minimum interval G1 of position adjustment by the eye intervaladjusting mechanism in the eye interval adjustment position aredisplayed in order. In the example shown in FIG. 11C, the lens positionsmatch the center positions of the eyes best in the interpolationposition +1 in the eye interval adjustment position, and thus acorrected image using the correction vectors for the interpolationposition +1 becomes a correct white-lined lattice image in whichchromatic aberration is rarely observed. On the other hand, as shown inFIGS. 11A and 11B, the centers of the eyes are shifted from the lenscenter to the left side in both interpolation positions −1 and 0, andthus a color shift becomes more conspicuous toward the right side of ascreen.

For example, information indicating the interpolation positions isdisplayed in an OSD manner together with the corrected image based onthe correction vectors in each of the interpolation positions, and auser may be allowed to select a correction vector of an interpolationposition to be used in correction among the vectors shown in FIGS. 11Ato 11C. Alternatively, adjustment may be automatically performed byreading the eye interval and the center positions of the eyes of a userusing a camera, or the like.

As described above, it is not necessary to use an eye interval adjustingmechanism that can perform adjustment with no stages, and a device costcan be cut. In addition, merely by changing a correction vector to beapplied to an input image, interpolation of the eye interval adjustingmechanism can be realized without making other changes in the design atall. In addition, by allowing a certain degree of distortion and amagnification chromatic aberration occurring in an observed image andsupplementing the allowed portion with image correction, a manufacturingcost of a lens can be lowered, and the weight of the lens can bereduced.

In addition, by changing the correction vectors stored in the correctionvector retaining unit 605, the distortion correction unit 202 canrespond to various aberrations caused by differences between individualusers.

As another example of aberration caused by differences betweenindividual users, when a person wearing glasses uses a head-mountdisplay, an aberration unique to the glasses occurs, and thus the usermay not be able to observe a correct image. In such a case, theaberration of the glasses is measured in advance, and correction vectorsfor correcting the aberration of the glasses are stored in thecorrection vector retaining unit 605. Then, when the person wearing theglasses wears the head-mount display, the distortion correction unit 602can present a correct image of which the aberration has been correctedeven when wearing the glasses by superimposing the correction vector forthe glasses on the correction vector for correcting lens distortion anda magnification chromatic aberration or the correction vector forinterpolating an eye interval position.

In addition, as another example resulting from differences betweenindividual users, with regard to the Z direction, that is, the distancedirection between the lens of the eyepiece optical system 604 and theeyes of a user, there are cases in which it is difficult to observe acorrect image because an aberration occurs due to a difference betweenan appropriate distance in terms of lens design and the distance of anindividual user, which may differ depending on users. Also in such acase, an aberration caused by the difference between the appropriatedistance in terms of lens design and the distance of an individual useris measured for the user in advance, and correction vectors are storedin the correction vector retaining unit 605. Then, when the user wears ahead-mount unit, a correct image of which an aberration has beencorrected can be presented to the user while wearing the glasses as thedistortion correction unit 602 superimposes a correction vector for thedifference between the appropriate distance and the distance of theindividual user on a correction vector for correcting lens distortionand a magnification chromatic aberration, or a correction vector forinterpolating an eye interval position.

Additionally, the present technology may also be configured as below.

-   (1)

A display device including:

a display unit that displays an image thereon;

an eyepiece optical unit that projects a display image of the displayunit on the eyes of a user;

a correction information retaining unit that retains correctioninformation created in advance according to a state of the user; and

a distortion correction unit that corrects distortion of the displayimage based on correction information according to a current state ofthe user.

-   (2)

The display device according to (1),

wherein the correction information retaining unit retains, as thecorrection information, a correction vector for correcting distortion ofthe display image caused by an amount of shift between the lens centerof the eyepiece optical unit and the center positions of the eyes of auser, and

wherein the distortion correction unit corrects the display image basedon the correction vector according to the amount of shift between thelens center of the eyepiece optical unit and the center positions of theeyes of the user.

-   (3)

The display device according to (1), further including:

an eye interval adjusting mechanism that adjusts a position of thedisplay unit with respect to the eye interval of a user in stages,

wherein the correction information retaining unit retains, as thecorrection information, a correction vector for correcting distortion ofthe display image caused by an amount of shift of an interpolationposition that is obtained by interpolating the interval of the stepwiseadjustment position by the eye interval adjusting mechanism, and

wherein the distortion correction unit corrects the display image basedon a correction vector according to an amount of shift of theinterpolation position remaining after the eye interval adjustingmechanism performs the adjustment.

-   (4)

The display device according to (1),

wherein the correction information retaining unit retains, as thecorrection information, a correction vector for correcting distortion ofthe display image caused by an aberration unique to glasses, and

wherein the distortion correction unit corrects the display image basedon a correction vector corresponding to the glasses that a user wears.

-   (5)

The display device according to (1),

wherein the correction information retaining unit retains, as thecorrection information, a correction vector for correcting distortion ofthe display image caused by the difference between an appropriatedistance in terms of lens design for the distance direction between alens of the eyepiece optical unit and the eyes of a user and thedistance of the individual user, and

wherein the distortion correction unit corrects the display image basedon the correction vector.

-   (6)

An image processing device including:

a correction information retaining unit that retains correctioninformation created in advance according to a state of a user; and

a distortion correction unit that corrects distortion of a display imagebased on correction information according to a current state of theuser.

-   (7)

An image processing method including:

retaining correction information that is created in advance according toa state of a user; and

correcting distortion of a display image based on correction informationaccording to a current state of the user.

-   (8)

A computer program that is described in a computer-readable form so asto cause a computer to function as:

a correction information retaining unit that retains correctioninformation created in advance according to a state of a user; and

a distortion correction unit that corrects distortion of a display imagebased on correction information according to a current state of theuser.

Hereinabove, the technology disclosed in the present specification hasbeen described in detail with reference to the specific embodiment.However, it is obvious that a person skilled in the art may find variousalternations and modifications within the scope of the appended claims.

In the present specification, although the embodiment in which thetechnology disclosed in the present specification is applied to ahead-mount display has been mainly described, the scope of thetechnology disclosed in the present specification is not limited to aconfiguration of a specific head-mount display. The technology disclosedin the present specification can be applied in the same manner tovarious types of display systems that include a combination of displaypanels and lenses in which images are presented to users.

In short, the technology disclosed in the present specification has beendescribed in the form of exemplification, which does not limit theinterpretation of the disclosed content of the present specification.When the gist of the technology disclosed in the present specificationis determined, claims thereof should be considered.

REFERENCE SIGNS LIST

-   10 head-mount unit-   20 Blu-ray disc reproduction device-   30 high-vision display-   40 front-end box-   601 video reduction unit-   602 distortion correction unit-   603 display unit-   604 eyepiece optical system-   605 correction vector retaining unit

The invention claimed is:
 1. A display device, comprising: a displayunit configured to display an image thereon; an eyepiece optical systemconfigured to project the displayed image of the display unit on eyes ofa user; an eye interval adjusting mechanism configured to adjust, instages, a position of the display unit with respect to an eye intervalof the user; and a computer configured to: create a first correctionvector to correct distortion of the displayed image caused by a firstamount of shift of an interpolation position, wherein the interpolationposition is obtained by interpolation of an interval between stepwiseadjustment positions of the eye interval adjusting mechanism; andcorrect the distortion of the displayed image based on the firstcorrection vector and based on the first amount of shift of theinterpolation position that remains after the eye interval adjustingmechanism adjusts the position.
 2. The display device according to claim1, wherein the computer is further configured to: create a secondcorrection vector to correct the distortion of the displayed imagecaused by a second amount of shift between a center of a lens of theeyepiece optical system and a center position of an eye, of the user,that corresponds to the lens; and correct the distortion of thedisplayed image based on the second correction vector.
 3. The displaydevice according to claim 1, wherein the computer is further configuredto: create a second correction vector to correct the distortion of thedisplayed image caused by an aberration unique to glasses; and correctthe distortion of the displayed image based on the second correctionvector that corresponds to the glasses that the user wears.
 4. Thedisplay device according to claim 1, wherein the computer is furtherconfigured to: create a second correction vector to correct thedistortion of the displayed image caused by a difference between adetermined distance based on lens design and a distance between a centerof a lens of the eyepiece optical system and a center position of aneye, of the user, that corresponds to the lens, and correct thedistortion of the displayed image based on the second correction vector.5. The display device according to claim 1, wherein the eyepiece opticalsystem comprises a first eyepiece optical system that corresponds to aleft eye of the user, and a second eyepiece optical system thatcorresponds to a right eye of the user, and wherein the computer isfurther configured to correct the distortion, of the displayed image,caused by a third amount of shift between a center of a first lens ofthe first eyepiece optical system and the left eye, or a fourth amountof shift between a center of a second lens of the second eyepieceoptical system and the right eye.
 6. The display device according toclaim 1, wherein the first amount of shift is smaller than the intervalbetween the stepwise adjustment positions of the eye interval adjustingmechanism.
 7. The display device according to claim 1, wherein theinterval between the stepwise adjustment positions of the eye intervaladjusting mechanism is a physical gap between the stepwise adjustmentpositions adjacent to each other.
 8. An image processing device,comprising: an eye interval adjusting mechanism configured to adjust, instages, a position of a display unit with respect to an eye interval ofa user; and a computer configured to: create a correction vector tocorrect distortion of a display image caused by an amount of shift of aninterpolation position, wherein the interpolation position is obtainedby interpolation of an interval between stepwise adjustment positions ofthe eye interval adjusting mechanism; and correct the distortion of thedisplay image based on the correction vector and based on the amount ofshift of the interpolation position that remains after the eye intervaladjusting mechanism adjusts the position.
 9. An image processing method,comprising: in an image processing device: adjusting, in stages by aneye interval adjusting mechanism, a position of a display unit withrespect to an eye interval of a user; creating a correction vector tocorrect distortion of a display image caused by an amount of shift of aninterpolation position, wherein the interpolation position is obtainedby interpolation of an interval between stepwise adjustment positions ofthe eye interval adjusting mechanism; and correcting the distortion ofthe display image based on the correction vector and based on the amountof shift of the interpolation position that remains after the positionis adjusted.
 10. A non-transitory computer-readable storage mediumhaving stored thereon computer-executable instructions that, whenexecuted by a processor, cause a computer to execute operations, theoperations comprising: adjusting, in stages by an eye interval adjustingmechanism, a position of a display unit with respect to an eye intervalof a user; creating a correction vector to correct distortion of adisplay image caused by an amount of shift of an interpolation position,wherein the interpolation position is obtained by interpolation of aninterval between stepwise adjustment positions of the eye intervaladjusting mechanism; and correcting the distortion of the display imagebased on the correction vector and based on the amount of shift of theinterpolation position that remains after the position is adjusted.